Use `PathEntryCollection.FirmwareAbsolutePath` extension

src/BizHawk.Client.Common/fwmanager/FirmwareManager.cs

@@ -145,7 +145,7 @@ namespace BizHawk.Client.Common
 			var reader = new RealFirmwareReader();
 
 			// build a list of files under the global firmwares path, and build a hash for each of them (as ResolutionInfo) while we're at it
-			var todo = new Queue<DirectoryInfo>(new[] { new DirectoryInfo(pathEntries.AbsolutePathFor(pathEntries.FirmwaresPathFragment, null)) });
+			Queue<DirectoryInfo> todo = [ new(pathEntries.FirmwareAbsolutePath()) ];
 			while (todo.Count != 0)
 			{
 				var di = todo.Dequeue();

src/BizHawk.Common/Extensions/CollectionExtensions.cs

@@ -65,6 +65,11 @@ namespace BizHawk.Common.CollectionExtensions
 			return min;
 		}
 
+		/// <remarks>for collection initializer syntax</remarks>
+		[MethodImpl(MethodImplOptions.AggressiveInlining)]
+		public static void Add<T>(this Queue<T> q, T item)
+			=> q.Enqueue(item);
+
 		/// <exception cref="InvalidOperationException"><paramref name="key"/> not found after mapping <paramref name="keySelector"/> over <paramref name="list"/></exception>
 		/// <remarks>implementation from https://stackoverflow.com/a/1766369/7467292</remarks>
 		public static T BinarySearch<T, TKey>(this IList<T> list, Func<T, TKey> keySelector, TKey key)